IBM 5162 (XT/286) hanging on boot

[seaken]

Hello all,

A couple of weeks ago I turned on my 5162 and it didn't boot. I thought at first it was the RLL hard drive since normally when I turn this machine on the C: drive boots up to DOS 3.3. But I don't think it's the RLL hard drive after pulling it out and putting it on my work bench this morning.

Normally when I turn this machine on I get the memory count and then a couple of beeps and am prompted to hit F1 to continue. After hitting F1 the hard drive proceeds to boot into DOS. But now all I am getting is the memory count displayed in the upper left on the monitor and then it stalls. The cursor is on the next line blinking, but no beeps and no F1 prompt.

When I power up I can see the keyboard lights blink. Then the memory counts up to 640K. Then nothing.

I am wondering why I don't get any beeps. I am not sure what the process is for it to beep and give me the F1 prompt. I'm assuming that's coming from the BIOS code but why is it stalling?

Here's what I've tried so far:

I took out all the interface cards. I put back only the mono video card (it is not the original IBM mono card but a third party card). I left the hard drive and floppy drive connected to power. When I powered it up after removing the cards the power supply comes on, the keyboard blinks, the memory count displays as before. But then it stalls. No change.

I removed the SIM memory chips and put them back in, reseating them. I pressed on the 128K memory chips, but did not remove them. I also pressed on the BIOS chips but did not remove them. Upon reboot it does the same thing. No change.

The labels on the BIOS chips indicate they are the original BIOS, according to the info on minuszerodgrees.net.

I do not have a POST card.

How should I proceed to troubleshoot this? Do I need a POST card?

The CMOS battery is completely dead. But up until now I was able to get it to boot even with the dead battery. Should I start by replacing the battery?

Thank you for any ideas you may have.

Seaken

 

[modem7]

The CMOS battery is completely dead. But up until now I was able to get it to boot even with the dead battery. Should I start by replacing the battery?

I am unaware of a low/dead CMOS battery causing this symptom on an IBM 5162.

I took out all the interface cards. I put back only the mono video card ...

Thank you for any ideas you may have.

The IBM 5170 is close to the IBM 5162.
The symptom that you describe has been seen on a 5170.
See the 'The RAM count-up happens on-screen, but no further progress even after a few minutes' entry at [here].
So check the position of the motherboard's display switch.

Do I need a POST card?

An ISA POST card would be helpful now, and for when things go bad later.

You have a third-party MDA card. That means that if you have the ability to program replacement BIOS ROM chips, then you could see what the AT version of the Supersoft/Landmark Diagnostic ROM shows.

 

[modem7]

I removed the SIM memory chips and put them back in, re-seating them.

From the IBM 5162 information at [here]:

"If either SIMM fails, the symptoms presented depend on the type of video card fitted:
* MDA or CGA card: You will see a 201 error which points to address 000000.
* Other: No visual nor audible indication. A POST card will reveal the situation"

 

[seaken]

Yes, thank you. I did not get a 201 error but I also don't have an IBM MDA card so wasn't sure if that would mean I have an "Other".

I will get a POST card.

Seaken

 

[seaken]

I switched SW1 to the other position. On power up I got one long beep and two short beeps. But I think the SW1 switch was in the correct position for the MDA card. At any rate, I cleaned the contacts and tried again. I tried with SW1 in both positions and the result was the same as before. No beeps, Hangs after memory test.

Assuming the MDA card is bad I took it out and installed a VGA card and attached a VGA Mono monitor. On reboot the RAM test shows on the top line and the VGA BIOS displays on the next two lines. But again, it hangs.

I took out the hard drive controller again and tyried to boot only with the floppy drive. It does the same. Hangs and never light up the floppy drive. It also does not beep or ask me to press F1. I am expecting it to ask me to press F1 and then go to Cassette Basic is it doesn't find the floppy. But I get nothing.

Hmm. BIOS chips?

Seaken

 

[modem7]

Yes, thank you. I did not get a 201 error but I also don't have an IBM MDA card so wasn't sure if that would mean I have an "Other".

With a third-party MDA card, if you remove either SIMM, you will see the 201 error pointing to address 000000. But I think we are going off track.

Hmm. BIOS chips?

The POST sequence for the 5162 is shown at [here]. If the BIOS chip/s are bad, then we expect the POST to stop at step 2 (POST code 02), halting after that (i.e. the POST does not proceed to the part that initialises the video card). But if you have the ability to create new BIOS ROM's, then give it a shot, just in case.

 

[modem7]

As a basic step, have you tried re-seating the CPU, just in case something weird is happening there ?

If it was my board, I would definitely be trying out the AT version of the Supersoft/Landmark Diagnostic ROM

 

[seaken]

Thank you. No I haven't tried re-seating the CPU yet. I guess I will go ahead and remove the MB from the case. Then I can try re-seating everything.

So, it's getting to the video initialization I think. All the video cards (MDA/CGA/VGA) have shown text on the screen with a blinking cursor.

Now, I assume the next step is to look for a boot record. I have read that if it does not find a boot record on disk it will boot into Cassette Basic. I used to get a beep after the memory test and then press F1 to boot either the floppy or hard drive. So, I think this is where it is getting stuck. Why don't I get a beep anymore?

Seaken

 

[seaken]

Now I am thinking about the floppy drive. I do not get a red light bump on the floppy when I turn on the machine. That may be a clue. But then why doesn't it just boot to Cassette Basic? Hmm. If I take out the floppy controller I don't get anything different. It just hangs with no beeps or F1 prompt. I will try swapping out the drive itself to see what happens. I don't have another floppy controller to swap in.

Seaken

 

[seaken]

Am I correct in thinking that Cassette Basic should be booting if there is no floppy or hard drive controller? If I am correct about that then what does it say to me if I never get into Basic?

If I am not correct about that, then what is supposed to happen if there is neither a floppy or hard drive controller in the machine?

Seaken

 

[Malc]

Am I correct in thinking that Cassette Basic should be booting if there is no floppy or hard drive controller? If I am correct about that then what does it say to me if I never get into Basic?

Yes, If NO bootable disk is found, It sounds like your 5162 is not completing POST for some reason.

If you can burn your own Eproms I would try out the AT version of the Supersoft diagnostic roms as Modem7 suggested in post #7.

 

[seaken]

Maybe I'll end up doing that. I don't currently have equipment to burn ROMs. It may be time to start learning more about repairing instead of just swapping parts around.

Seaken

 

[seaken]

I think I will start by re-seating everything and using some deoxit cleaner. If that doesn't work I'll start purchasing more tools like the ROM burner and POST card.

I wonder if I can buy updated ROM chips already burned?

Seaken

 

[Malc]

I wonder if I can buy updated ROM chips already burned?

There are some folks who can burn eproms on Modem7's website https://minuszerodegrees.net/rom/misc/eprom_programming_services.htm

 

[modem7]

... and installed a VGA card and attached a VGA Mono monitor. On reboot the RAM test shows on the top line and the VGA BIOS displays on the next two lines. But again, it hangs.

So, it's getting to the video initialization I think.

Definitely. The only way that the VGA BIOS can display its banner text is if step 23 at [here] happens. (Step 23 executes the initialisation code in the VGA BIOS ROM.)

What you are experiencing is not by design. Once video initialisation happens (MDA/CGA/EGA/VGA) any error indication is then displayed on-screen. Per what Malc wrote, it appears that something is resulting in the POST unexpectedly stopping.

The POST card might help diagnosis.

A new ROM set is worth a shot. There is the rare possibility that bits have changed in the ROM, but in a pattern that results in the 8-bit checksum of the ROM staying at 00 (and therefore, the POST believing that the ROM's are not corrupted).

 

[seaken]

I pulled out the MB and cleaned it. There were some dust bunnies under the board but overall it was not very dirty. I pulled and re-seated the CPU, both BIOS chips, and the RAM chips. But unfortunately it is still in the same state.

I think I read that the Cassette BASIC is part of the BIOS? In that case, if I replace the BIOS with say an AMI BIOS, will I lose the IBM Cassette BASIC?

Seaken

 

[modem7]

I think I read that the Cassette BASIC is part of the BIOS? In that case, if I replace the BIOS with say an AMI BIOS, will I lose the IBM Cassette BASIC?

Yes.

 

[seaken]

Thank you @modem7 . I appreciate the information.

I think it's likely that the BIOS chips have gone bad for some reason. I guess I will need to replace the BIOS to find out for sure. Hopefully that will get me back to a working system.

This is a very important system to me. It's the closest I have to our original IBM PC/XT. I would like to keep it working.

I will try to use the BIOS you recommended above. Landmark? Now I just need to learn how to do it.

Thank you again,

Seaken

 

[modem7]

I will try to use the BIOS you recommended above. Landmark? Now I just need to learn how to do it.

Obviously, there will be a learning curve when you get your EPROM programmer.
At the high level, the steps are:
1. Programmer app: Select the make-model of EPROM/EEPROM that you are going to program.
2. Programmer app: Import the data/image file (typically has the .BIN extension).
3. Programmer app: Place EPROM/EEPROM into socket (per the position shown by the app).
4. Programmer app: Perform a 'Verify empty' operation.
5. Programmer app: Perform a 'Program' operation.

For my IBM 51xx machines, I use W27E257 EEPROM's, but other options are available. See the 'IBM 5162' section of [here].

If you go the EPROM route (rather than EEPROM), you will need to get yourself an EPROM erasing box. Example at [here].

As for the the Supersoft/Landmark Diagnostic ROM, image files (BIN files) for the AT version are available via the web page at [here].

 

[seaken]

Whew! This is pretty dizzying stuff! I think I have narrowed it down to a MiniPro TI866 programmer. But there are so many advertisements I am having a hard time sorting it out. Which is the best resource for these things? Is AliExpress the right source? Amazon? Ebay?

I'll take my time sorting it out. But maybe you guys can give me some guidance on which programmer to buy? It does have to support the old IBM PC stuff. Much of what I've seen on videos is for much newer stuff. I'm a little out of my depth and forty years has gone by.

I'm good with downloading the image files from the website. It's buying the programmer that is confusing.

Seaken